Hi, i would like to define a wall as a perfekt wall which doesnt transfer heat. At first i thought i could define them as adiabatic, but later i found out that an adiabatic wall isnt a perfect insulated wall. So does anyone know how i can fix this problem. My only idea at the moment is to define the wall with a construction which has a realy small U-value.
In EnergyPlus/OpenStudio, an adiabatic boundary condition applies the same boundary to both sides of the construction. This means that heat is allowed to be stored in the wall, but it cannot transfer through.
If you don't want any heat flow at all, you can either remove the wall from the simulation altogether OR you can define a construction with a very low U-value as you mentioned.
Consider a highly conductive wall with the same temperature on either side of the wall. If there is no temperature difference, then there is not heat transfer. If the temperature on both sides of the wall were to increase, then heat would flow into the wall, but because of the symmetric boundary condition heat would not flow through the wall to the other side.
ok, i designed a building which is connected with another building. Both buildings have the same temperature. In my model is only one of this two buildings. When i define the wall which is conected to the building next to it as adiabatic, would that mean that there is not heat transfer to the outside? Or would it be better to define it with a low U-value?
If you truly want a wall that does not participate in the zone heat transfer (does not store heat or conduct heat, does not radiate to other surfaces, etc.) then simply delete it from the model. Nothing will happen across that plane. But from your description of the overall model, it seems that what you really want is an adiabatic wall that will add thermal mass but not conduct to/from the outside of the zone.
Asked: 2015-01-15 10:00:44 -0500
Seen: 298 times
Last updated: Jan 16 '15
@Marcelba, can you add a tag for the simulation tool are you using (e.g., eQUEST, OpenStudio, EnergyPlus)